Merge pull request #849 from DarkLordZach/xci

XCI and Encrypted NCA Support

1 files changed, 112 insertions, 0 deletions

diff --git a/src/core/crypto/aes_util.cpp b/src/core/crypto/aes_util.cpp
new file mode 100644
index 000000000..4690af5f8
--- /dev/null
+++ b/src/core/crypto/aes_util.cpp
@@ -0,0 +1,112 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <mbedtls/cipher.h>
+#include "core/crypto/aes_util.h"
+#include "core/crypto/key_manager.h"
+
+namespace Core::Crypto {
+
+static_assert(static_cast<size_t>(Mode::CTR) == static_cast<size_t>(MBEDTLS_CIPHER_AES_128_CTR),
+              "CTR has incorrect value.");
+static_assert(static_cast<size_t>(Mode::ECB) == static_cast<size_t>(MBEDTLS_CIPHER_AES_128_ECB),
+              "ECB has incorrect value.");
+static_assert(static_cast<size_t>(Mode::XTS) == static_cast<size_t>(MBEDTLS_CIPHER_AES_128_XTS),
+              "XTS has incorrect value.");
+
+// Structure to hide mbedtls types from header file
+struct CipherContext {
+    mbedtls_cipher_context_t encryption_context;
+    mbedtls_cipher_context_t decryption_context;
+};
+
+template <typename Key, size_t KeySize>
+Crypto::AESCipher<Key, KeySize>::AESCipher(Key key, Mode mode)
+    : ctx(std::make_unique<CipherContext>()) {
+    mbedtls_cipher_init(&ctx->encryption_context);
+    mbedtls_cipher_init(&ctx->decryption_context);
+
+    ASSERT_MSG((mbedtls_cipher_setup(
+                    &ctx->encryption_context,
+                    mbedtls_cipher_info_from_type(static_cast<mbedtls_cipher_type_t>(mode))) ||
+                mbedtls_cipher_setup(
+                    &ctx->decryption_context,
+                    mbedtls_cipher_info_from_type(static_cast<mbedtls_cipher_type_t>(mode)))) == 0,
+               "Failed to initialize mbedtls ciphers.");
+
+    ASSERT(
+        !mbedtls_cipher_setkey(&ctx->encryption_context, key.data(), KeySize * 8, MBEDTLS_ENCRYPT));
+    ASSERT(
+        !mbedtls_cipher_setkey(&ctx->decryption_context, key.data(), KeySize * 8, MBEDTLS_DECRYPT));
+    //"Failed to set key on mbedtls ciphers.");
+}
+
+template <typename Key, size_t KeySize>
+AESCipher<Key, KeySize>::~AESCipher() {
+    mbedtls_cipher_free(&ctx->encryption_context);
+    mbedtls_cipher_free(&ctx->decryption_context);
+}
+
+template <typename Key, size_t KeySize>
+void AESCipher<Key, KeySize>::SetIV(std::vector<u8> iv) {
+    ASSERT_MSG((mbedtls_cipher_set_iv(&ctx->encryption_context, iv.data(), iv.size()) ||
+                mbedtls_cipher_set_iv(&ctx->decryption_context, iv.data(), iv.size())) == 0,
+               "Failed to set IV on mbedtls ciphers.");
+}
+
+template <typename Key, size_t KeySize>
+void AESCipher<Key, KeySize>::Transcode(const u8* src, size_t size, u8* dest, Op op) {
+    size_t written = 0;
+
+    const auto context = op == Op::Encrypt ? &ctx->encryption_context : &ctx->decryption_context;
+
+    mbedtls_cipher_reset(context);
+
+    if (mbedtls_cipher_get_cipher_mode(context) == MBEDTLS_MODE_XTS) {
+        mbedtls_cipher_update(context, src, size, dest, &written);
+        if (written != size)
+            LOG_WARNING(Crypto, "Not all data was decrypted requested={:016X}, actual={:016X}.",
+                        size, written);
+    } else {
+        const auto block_size = mbedtls_cipher_get_block_size(context);
+
+        for (size_t offset = 0; offset < size; offset += block_size) {
+            auto length = std::min<size_t>(block_size, size - offset);
+            mbedtls_cipher_update(context, src + offset, length, dest + offset, &written);
+            if (written != length)
+                LOG_WARNING(Crypto, "Not all data was decrypted requested={:016X}, actual={:016X}.",
+                            length, written);
+        }
+    }
+
+    mbedtls_cipher_finish(context, nullptr, nullptr);
+}
+
+template <typename Key, size_t KeySize>
+void AESCipher<Key, KeySize>::XTSTranscode(const u8* src, size_t size, u8* dest, size_t sector_id,
+                                           size_t sector_size, Op op) {
+    if (size % sector_size > 0) {
+        LOG_CRITICAL(Crypto, "Data size must be a multiple of sector size.");
+        return;
+    }
+
+    for (size_t i = 0; i < size; i += sector_size) {
+        SetIV(CalculateNintendoTweak(sector_id++));
+        Transcode<u8, u8>(src + i, sector_size, dest + i, op);
+    }
+}
+
+template <typename Key, size_t KeySize>
+std::vector<u8> AESCipher<Key, KeySize>::CalculateNintendoTweak(size_t sector_id) {
+    std::vector<u8> out(0x10);
+    for (size_t i = 0xF; i <= 0xF; --i) {
+        out[i] = sector_id & 0xFF;
+        sector_id >>= 8;
+    }
+    return out;
+}
+
+template class AESCipher<Key128>;
+template class AESCipher<Key256>;
+} // namespace Core::Crypto
\ No newline at end of file